For diagram of the 3-hydroxypropanoate cycle, click here, for diagram of the 3-hydroxypropanoate/4-hydroxybutanoate cycle and dicarboxylate/4-hydroxybutanoate cycle in archaea, click here and for diagram of 3-(dimethylsulfonio)propanoate met

Catalyses a step in the 3-hydroxypropanoate/4-hydroxybutanoate cycle, an autotrophic CO2 fixation pathway found in some thermoacidophilic archaea [1]. The enzyme from Sulfolobus tokodaii does not act on either NADH or crotonyl-CoA [2]. Different from EC 1.3.1.8, which acts only on enoyl-CoA derivatives of carbon chain length 4 to 16. Contains Zn2+.